1. Field of the Invention
The present invention relates to an electronic-part mounting apparatus for mounting electronic parts on a printed-wiring board and more particularly to an electronic-part mounting apparatus for manually mounting chip-type electronic parts on a printed-wiring board.
2. Description of the Related Art
An electronic-part mounting apparatus for mounting electronic parts on a printed-wiring board, particularly an automatic electronic-part mounting apparatus for automatically mounting electronic parts are widely known.
An automatic electronic-part mounting apparatus will be described with reference to FIG. 1 by way of example. The automatic electronic-part mounting apparatus shown in FIG. 1 has an electronic-part supply device 210 for continuously supplying chip-type electronic parts, a mounting head 220 for carrying the electronic parts to a positioning position on a printed-wiring board 50 with holding the electronic parts by attraction, a positioning unit 221 for positioning the electronic parts at the positioning position, and an XY table 230 for supporting the printed-wiring board 50 so that the printed-wiring board 50 can be moved in the.X and Y directions.
The chip-type electronic parts have various types or various shapes. Typically, the chip-type electronic parts have a rectangular shape and have, in view of a dimension, a width ranging from 1.0 to 1.2 mm, a length ranging from 1.8 mm to 2.0 mm and a height ranging from 0.4 to 0.5 mm.
The electronic-part supply device 210 employs a so-called carrier tape system. In the carrier tape system, the chip-type electronic parts are taped at a constant interval by a long carrier tape 211 wound around a reel. The carrier tape 211 is usually formed of two tapes, i.e., a top tape on its front side and a bottom tape on its rear side, and the electronic parts are supported while being gripped between the two tapes. A plurality of part cassettes 212 each including such reel are loaded onto the electronic-part supply device 210.
The electronic-part supply deice 210 may employ a system of supplying chip-type electronic parts individually housed in a bulk case other than the carrier tape system. The system of individually supplying the electronic parts is called a bulk feeder in which the electronic parts are housed in a plastic bulk case and the bulk case is loaded onto the electronic-part supply device.
The mounting head 220 has a rotary table 222 which can be rotated about a center axis and a plurality of attracting nozzles 223. The attracting nozzles 223 are fitted along a circumferential direction of the rotary table 222. As the rotary table 222 is rotated, the attracting nozzles 223 are also rotated. The attracting nozzles 223 are moved among an attracting position where the attracting nozzles 223 attract the electronic parts supported on the carrier tape 211, the positioning position where the positioning unit 221 positions the electronic parts, and a mounting position where the electronic parts are mounted on the printed-wiring board 50.
An operation of the automatic electronic-part mounting apparatus will subsequently be described. Initially, the printed-wiring board 50 is conveyed from a loading station onto the XY table 230. The attracting nozzle 223 located at the attracting position attracts the chip-type electronic parts, and the rotary table 222 is rotated. Thereafter, the attracting nozzle 223 is moved to the positioning position.
At the positioning position, the positioning unit 221 positions the electronic parts. When the operation of positioning the electronic parts is finished, the rotary table 222 is rotated and consequently the attracting nozzle 223 is moved to the mounting position. At the mounting position, the attracting nozzle 223 is lifted down to mount the electronic parts, which the attracting nozzle has held, on the printed-wiring board 50.
When the electronic parts are mounted on the printed-wiring board 50, the XY table 230 is moved to the next mounting position. When this operation is repeatedly carried out and consequently all the electronic parts have been mounted on the printed-wiring board, the printed-wiring board 50 is returned to the initial position. Finally, the printed-wiring board 50 is ejected from the XY table 230 to an unloading position. This sequential operation is repeated.
According to the automatic electronic-part mounting apparatus shown in FIG. 1, the chip-type electronic parts are successively mounted on the printed-wiring board 50 one by one. Every time when one of the chip-type electronic parts is mounted on the printed-wiring board, the attracting nozzle 223 must be lifted down and up. Thereafter, the rotary table 222 is rotated and then the attracting nozzle 223 is lifted down and up again Operations of the attracting nozzle 223 and the rotary table 232 are carried out in a predetermined order.
In order to carry out efficiently the electronic-part mounting process, it is necessary to reduce a time required for mounting one electronic part. For this end, it may be sufficient to increase speeds of movements of the attracting nozzle 223 and the rotary table 222. However, even if the speeds are increased, it is impossible to reduce the time required for mounting one electronic part beyond a certain extent. Therefore, it is impossible to increase the speeds beyond the limit.
Even if the time required for mounting one electronic part can be reduced, a time required for carrying out the electronic-part mounting process becomes longer as the number of the electronic parts to be mounted on one printed-wiring board 50 is increased.
When the automatic electronic-part mounting apparatus shown in FIG. 1 is employed, if the number of the electronic parts to be mounted is increased or if it is necessary to carry out the mounting operation at higher speed, then the apparatus tends to become large in size and to become complicated, which requires more costs and limits a room where the apparatus is located.
Since the automatic electronic-part mounting apparatus shown in FIG. 1 is arranged so as to automatically mount the electronic parts on the printed-wiring board 50, the conventional automatic electronic-part mounting apparatus shown in FIG. 1 requires a drive mechanism and a control device, which complicates an arrangement of the automatic electronic-part mounting apparatus shown in FIG. 1 and makes a size thereof larger.
The automatic electronic-part mounting apparatus shown in FIG. 1 employs a process for checking the electronic parts mounted on the printed-wiring board 50. This checking process is carried out by using a considerable expensive apparatus utilizing a video processing technique, for example, or the like. Therefore, the automatic electronic-part mounting apparatus shown in FIG. 1 inevitably includes the disadvantage that its arrangement becomes complicated and hence costs of equipment is increased.